x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 92 insertions, 0 deletions

diff --git a/Documentation/scsi/bfa.rst b/Documentation/scsi/bfa.rst
new file mode 100644
index 000000000..3abc04118
--- /dev/null
+++ b/Documentation/scsi/bfa.rst
@@ -0,0 +1,92 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=========================================
+Linux driver for Brocade FC/FCOE adapters
+=========================================
+
+Supported Hardware
+------------------
+
+bfa 3.0.2.2 driver supports all Brocade FC/FCOE adapters. Below is a list of
+adapter models with corresponding PCIIDs.
+
+	===================	===========================================
+	PCIID			Model
+	===================	===========================================
+	1657:0013:1657:0014	425 4Gbps dual port FC HBA
+	1657:0013:1657:0014	825 8Gbps PCIe dual port FC HBA
+	1657:0013:103c:1742	HP 82B 8Gbps PCIedual port FC HBA
+	1657:0013:103c:1744	HP 42B 4Gbps dual port FC HBA
+	1657:0017:1657:0014	415 4Gbps single port FC HBA
+	1657:0017:1657:0014	815 8Gbps single port FC HBA
+	1657:0017:103c:1741	HP 41B 4Gbps single port FC HBA
+	1657:0017:103c 1743	HP 81B 8Gbps single port FC HBA
+	1657:0021:103c:1779	804 8Gbps FC HBA for HP Bladesystem c-class
+
+	1657:0014:1657:0014	1010 10Gbps single port CNA - FCOE
+	1657:0014:1657:0014	1020 10Gbps dual port CNA - FCOE
+	1657:0014:1657:0014	1007 10Gbps dual port CNA - FCOE
+	1657:0014:1657:0014	1741 10Gbps dual port CNA - FCOE
+
+	1657:0022:1657:0024	1860 16Gbps FC HBA
+	1657:0022:1657:0022	1860 10Gbps CNA - FCOE
+	===================	===========================================
+
+
+Firmware download
+-----------------
+
+The latest Firmware package for 3.0.2.2 bfa driver can be found at:
+
+http://www.brocade.com/services-support/drivers-downloads/adapters/Linux.page
+
+and then click following respective util package link:
+
+	=========	=======================================================
+	Version		Link
+	=========	=======================================================
+	v3.0.0.0	Linux Adapter Firmware package for RHEL 6.2, SLES 11SP2
+	=========	=======================================================
+
+
+Configuration & Management utility download
+-------------------------------------------
+
+The latest driver configuration & management utility for 3.0.2.2 bfa driver can
+be found at:
+
+http://www.brocade.com/services-support/drivers-downloads/adapters/Linux.page
+
+and then click following respective util package link
+
+	=========	=======================================================
+	Version		Link
+	=========	=======================================================
+	v3.0.2.0	Linux Adapter Firmware package for RHEL 6.2, SLES 11SP2
+	=========	=======================================================
+
+
+Documentation
+-------------
+
+The latest Administration's Guide, Installation and Reference Manual,
+Troubleshooting Guide, and Release Notes for the corresponding out-of-box
+driver can be found at:
+
+http://www.brocade.com/services-support/drivers-downloads/adapters/Linux.page
+
+and use the following inbox and out-of-box driver version mapping to find
+the corresponding documentation:
+
+	=============		==================
+	Inbox Version		Out-of-box Version
+	=============		==================
+	v3.0.2.2		v3.0.0.0
+	=============		==================
+
+Support
+-------
+
+For general product and support info, go to the Brocade website at:
+
+http://www.brocade.com/services-support/index.page